An animal rights group Tuesday released an undercover video it says depicts cruelty at a Pipestone hog farm, including slamming piglets to death on the floor.

But the hog farm management company says practices depicted in the video — including killing piglets through “blunt force trauma” — are all within hog industry guidelines.

The video from Mercy for Animals was taken surreptitiously on behalf of the group by an employee at Rosewood Farm, which is part of the Pipestone System, a group of more than 200 hog farmers who share services.

The video shows sows confined in cramped gestation crates — a common practice — and piglets getting castrated or having their tails removed without anesthesia.

As for piglets killed on the production floor, “it’s called thumping and it can be horribly cruel,” said Nathan Runkle, the group’s executive director. They are killed because “they are not growing as fast as other pigs. They are runts,” he said.

Luke Minion, CEO of the Pipestone Management Co., said piglets are euthanized because they are sickly and may have breathing problems or broken bones.

The practice is approved by the National Pork Producers Council, and is “very fast and pain free,” he said.

With all of its farmers together, the Pipestone system is a major pork producer. The Rosewood Farm facility is owned by an affiliate of Randy Spronk, Minion confirmed. Spronk, who could not be reached for comment, is currently head of the National Pork Producers Association.

Mercy for Animals asked a Pipestone County judge for a search warrant of Rosewood on the grounds of animal cruelty. The judge issued the warrant this month and the Pipestone County Sheriff’s Office searched the operation. The Pipestone County attorney declined to press charges.

The incident marks the second time in just over a year that Mercy for Animals has successfully planted an employee at a Minnesota hog farm. In July 2012, the group released an undercover video shot at a south-central farm owned by Christensen Farms, a major hog producer. That video showed similar practices seen in the Pipestone System video.

Mike Hughlett covers energy and other topics for the Star Tribune, where he has worked since 2010. Before that he was a reporter at newspapers in Chicago, St. Paul, New Orleans and Duluth.